MRI of radiation-induced prostate sarcoma.

A patient with a history of pelvic radiation therapy for seminoma presented with a prostatic tumor, which appeared predominantly of high signal intensity on T2-weighted magnetic resonance images; low-signal-intensity tissue also extended to the pelvic sidewall. At surgical pathology, the tumor was determined to be radiation-induced sarcoma of the prostate, and the extraprostatic tissue was postradiation fibrosis.